Jacob Matthews <jacobm at cs.uchicago.edu> writes:
> For list-related administrative tasks:
>http://list.cs.brown.edu/mailman/listinfo/plt-scheme>> On Thu, 29 May 2003, andrew cooke wrote:
>> > to make this explicit, consider storing "foo" with key 'j and (for
> > simplicity) a hashtable so big that array indices are hash values.
> > at the time of storage the hash code of 'j is 42, so we put "foo" at
> > index 42. later, after garbage collection, we want to recover the
> > value associated with 'j. so we get the hashcode of 'j, which is
> > now 666, and don't find anything. that's not right, surely?
>> The key insight here is that as long as anyone has a reference to a
> particular symbol value, its hash code won't change. So the fact that our
> tree structure holds onto 'a if someone inserts it (as opposed
> to merely holding onto 'a's hash code) ensures that 'a = 'a
> and (eq-hash-code 'a) = (eq-hash-code 'a) everywhere. Therefore our
> structure doesn't have a bug.
ah! ok. thanks. sorry for the noise.
cheers,
andrew
--
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